Nc/12sep/perf (#1702)

* Remove unused fil;e

* Add benchmark-fast command for running locally

* Small improvements to jsonplus serializer

* Don't use PregelNode.mapper when schema is a typed dict

- All it would do is create a new copy of same dict

* Avoid copying checkpoint when fetching at beginning of loop

* Fix needs array

* Update tests

.github/workflows/bench.yml

@@ -14,7 +14,6 @@ jobs:
     defaults:
       run:
         working-directory: libs/langgraph
-    needs: [baseline]
     steps:
       - uses: actions/checkout@v4
       - id: files